Thermostatic ventilation button for orthopedic devices



Sept. 5, 1961 M. H. CHESTER THERMOSTATIC VENTILATION BUTTON FOR ORTHOPEDIC DEVICES Filed June 26, 1959 INVENTOR. MARTIN H. CHESTER AGENT 2,998,921 THERMOSTATIC VENTILATION BUTTON FOR ORTHOP-EDIC DEVICES Martin H. Chester, 16000 S. Vermont Ave., Gardena,, Calif. Filed June 26, 1959, Ser. No. 823,254 6 Claims. (Cl. 23649) This invention relates to a thermostatic ventilation button for orthopedic devices and more particularly to such a ventilation button which will automatically regulate the ventilation to body surfaces covered by orthopedic devices.

Orthopedic devices which cover parts of the body such as sacroiliac supports, braces, belts, cervical collars, and ordinary plaster casts must often be kept over the body surface involved for considerable periods of time. The close covering provided by such devices generally causes considerable skin irritation and resultant discomfort to the patient. If the patient should have intermittent fever and especially in hot weather, the discomfort and skin irritation may become a serious problem. The combination of moisture and heat may produce serious maceration of the skin which may result in skin ulcers and secondary infection. Various devices have been developed to alleviate this problem. These include ventilation plugs and removable windows formed in plaster casts. Both of these types of devices require manual control and provide no precise means for regulation to attain the optimum amount of ventilation.

The device of this invention provides a simple, yet effective means for automatically providing ventilation in orthopedic devices. The amount of ventilation provided is automatically regulated for optimum results. No manual adjustment is necessary with changing heat conditions. The device itself sets the ventilation in accordance with the ambient temperature both under the orthopedic covering and on its outside.

A number of heat sinks which have separate heat pickup portions exposed respectively to the outside and the inside of the orthopedic covering are provided to sense the ambient temperature. These heat sinks are each attached to a separate bimetallic strip. The bimetallic strips are all attached to a valve head. The valve head is either moved towards its seat or away from this seat by the bimetallic strips depending upon the temperature of the strips which is determined by the ambient temperature which controls the temperature of the heat sinks. In this manner, the amount of air passing through the valve is automatically regulated in accordance with the surrounding temperature.

It is therefore an object of this invention to provide means for automatically furnishing ventilation to portions of the body covered by orthopedic devices.

It is a further object of this invention to minimize the skin irritation and discomfort to patients wearing orthopedic devices.

It is another object of this invention to provide an improved means for ventilating in orthopedic devices.

It is a still further object of this invention to minimize moisture and heat within the confines of orthopedic devices and thereby prevent maceration and ulceration of skin surfaces covered by such devices.

It is still another object of this invention to provide means for automatically regulatingventilatio'n in body coverings. Y

Other objects of this invention will become apparent from the following description of the device of the invention taken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view of a preferred embodiment of the device of the invention, and

nited Smtcs Patent 6 M Patented Sept. 5, 1961 FIG. 2 is a cross-sectional elevation view of the device as illustrated in FIG. 1 taken along a plane as indicated by the line 2-4. in FIG. 1.

Referring to FIGS. 1 and 2, a preferred embodiment of the invention is illustrated. The drawings are enlarged several times over the normally contemplated size of the device of the invention (approximately one inch in diameter). Heat sinks 18 which in the embodiment illustrated are four in number may be any desired number depending on design. These heat sinks are imbedded in support portion 9 which may be fabricated of a relatively low heat conductive material such as plastic. Heat sinks 18 are fabricated of a highly heat conductive material such as, for example, brass or copper. To each of heat sinks 18 a separate bimetallic strip 12. is fixedly attached, one end of each strip being joined to its associated heat sink 18 at approximately the longitudinal center of the heat sink. Bimetallic strips 12. may be conventionally designed with two metals having highly difr'ering coefficients of linear expansion such as, for example, brass and steel. The two metal strips should be joined together, for example, by welding or braking, with the strip of the metal having the high coefficient of expansion being positioned on the bottom (as illustrated in FIG. 2) i.e., adjacent the upper surface of valve head member 14. Bimetallie strips 12 are fixedly attached by cementing or any other suitable means to valve head member 14 which is fabricated ofa low heat conductive material such as, for example, plastic.

Main support member 9 has a valve seat portion 16 which mates with circular valve head member 14. Main support portion 9 also has an upper circular mounting flange 25 forming part of an upper broad surface and a lower circular flange 24 wider than flange 25 which forms part of a lower broad surface opposite the upper surface. Each of the heat sinks 18 has two widened portions one of which protrudes through the upper broad surface of the support portion 9, the other of which protrudes through the lower broad surface of support member 9. The upper widened portion of the heat sink serves to transmit the outside ambient temperature while the lower widened portion serves to transmit the temperature radiated from the body surface covered by the orthopedic device. The heat sing thus receives inputs from both these heat sources and tends to transmit their differential to its associated bimetallic strip 12. In this manner, the valve is made responsive to changes in the outside ambient temperature as well as to the temperature of the covered body area. This tends to anticipate probable body temperature changes due to variations in the outside ambient temperature and makes for more effective temperature regulation.

A mounting strip 27 is provided to support adjusting screw 22. Mounting strip 27 which may be fabricated of a low heat conductive material such as plastic is fixedly attached at each of its ends to main support member 9 by suitable means such as cementing. Adjusting screw 22 is adjustably mounted in the center of mounting strip 27. The adjusting screw may be set within an associated threaded portion of the mounting strip so that its as extensions of main support member 9 to facilitate the mounting of theventilati'on button within an ortho-- Asindicated in FIG. 2,'these -mountingi pedic device. flanges provide surfaces around which plaster coated bandage may readily be wound to form a plaster cast 20. These mounting flanges are also suitable as means for attachment to other materials such as canvas, heavy cloth or felt which are also commonly used in orthopedic devices. It is' to be noted that support portion 9 in effect provides a case for the movable parts of the ventilation button and acts to prevent material such as plaster used in the orthopedic device from falling on these parts and impairing their operation.

It is to be noted also that while four bimetallic strips 12 and four associated heat sinks 18 have been shown in the illustrated embodiment, a greater or lesser number of strips and sinks may be used if so desired.

The device of this invention thus provides a simple yet eflective means for automatically providing ventilation in orthopedic devices. If so desired, the device may also be used to provide ventilation in surgical drapes, blankets, clothing, or other articles used as body coverings.

While the device of the invention has been described and illustrated in detail, it is to be clearly understood that this is intended by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the invention being limited only by the terms of the following claims.

I claim:

1. A thermostatically controlled ventilation button for use with orthopedic devices comprising a main support member fabricated of a material having low heat conductivity, a plurality of heat sink members having high heat conductivity mounted within said support member, said heat sink members having widened portions on opposite ends thereof, said widened portions protruding through opposite surfaces of said support member, a plurality of bimetallic strips, each of said bimetallic strips being fixedly attached at one end thereof to a separate one of said heat sink members, and a valve head fixedly attached to the end of each of said bimetallic strips opposite said one end attached to said heat sink members, said support member having a surface positioned opposite a surface of said valve head shaped to mate with said valve head to form a seat therefor, said main support member further having a portion shaped to form a wall surrounding said heat sink, said metallic strips, and said valve head.

2. The device as recited in claim 1 wherein said valve head and said main support member are circularly shaped.

3. A thermostatic ventilation button for body coverings comprising a mm'n support member fabricated of a low heat conductive material, a plurality of heat sink members mounted within said main support member, said heat sink members being fabricated of a material having high heat conductivity, a plurality of bimetallic strips, each of said strips being fixedly attached at one end thereof to a respective one of said heat sink members, said heat sink members each having two widened portions of increased surface area, one of each of said widened portions protruding through one broad surface of said support member, the other of each of said widened portions protruding through the surface of said support member opposite said one surface, and a valve head member fabricated of a material having low heat conductivity, the ends of each of said bimetallic strips opposite said one end attached to said heat sink members being fixedly attached to said valve head member, said main support member having a portion thereof shaped to form a valve seat for said valve head, said valve seat portion being positioned opposite said head member and adapted to mate therewith. V

4. A thermostatic ventilation button for orthopedic devices comprising a main support member fabricated of a low heat conductive material, a plurality of heat sink members mounted within said main support member, said heat sink members being fabricated of a material having high heat conductivity, a plurality of bimetallic strips, each of said strips being fixedly attached at one end thereof to a respective one of said heat sink members, said heat sink members each having two widened portions of increased surface area, one of each of said widened portions protruding through one broad surface of said support member, the other of each of said widened portions protruding through the surface of said support member opposite said one surface, a valve head member fabricated or" a material having low heat conductivity, the ends of each of said bimetallic strips opposite said ends attached to said heat sink members being fixedly attached to said valve head member, said main support member having a portion thereof shaped to form a valve seat for said valve head member, said valve seat portion being positioned opposite said valve hea'd member and adapted to mate therewith a mounting strip, the ends of said mounting strip being fixedly attached to said main support member, an adjusting screw threadably mounted on said mounting strip, one end of said screw abutting against said valve head member, said main support members having two mounting flanges, one of said flanges forming part of said one broad surface of said main support member, the other of said flanges forming part of the surface opposite said one broad surface of said support member.

5. A thermostatically controlled ventilation button for use with orthopedic devices comprising a main support member fabricated of a low heat conductive material, a plurality of heat sink members mounted within said support member, said heat sink members being fabricated of a material having high heat conductivity, a plurality of bimetallic strips, each of said strips being fixedly attached at one end thereof to a respective one of said heat sink members, each of said heat sink members having two widened portions of increased surface area, one of each of said widened portions protruding through one broad surface of said support member, the other of said widened portions of each of said heat sink members protruding through the surface of said support member opposite said one broad surface, a circularly shaped valve head member fabricated of a material having low heat conductivity, the ends of each of said bimetallic strips opposite the ends attached to said heat sink members being fixedly attached to said valve head member, said main support member having a portion shaped to mate with said valve head as a seat therefore, said seat portion of said main support member being positioned opposite said valve head member, said main support member having a cylindrical wall portion, said main support member further having an upper circular flange extending in the same plane as said one broad surface of said main support from one end of said cylindrical wall and a lower circular flange extending in the same plane as said surface opposite said one broad surface from the end of said cylindrical wall opposite said one end thereof, a mounting strip fixedly attached to said main support portion, and an adjustment screw threadably mounted in said mounting strip, one end of said screw abutting against said valve head member.

6. The device as recited in claim. 5 wherein said lower flange extends further from said cylindrical wall than said upper flange.

References Cited in the file of this patent UNITED STATES PATENTS 1,918,272 Kopsa et al. July 18, 1933 2,171,767 Scheu Sept. 5, 1939 2,396,820 Breese Mar. 19, 1946 2,704,067 Moses Mar. 15, 1955 2,828,919 Hillebrand Apr. 1, 1958 2,855,922 Schroeder Oct. 14, 1958 

